The issue is the belief that life originated from non life and then improved error by error until there were brilliant humans. If they can find life anywhere beyond earth, that would prove (in their minds) their fervent beliefs.
And if we found intelligent life that communicated with us and confirmed their beliefs, they would be in heaven, so to speak.
I think the problem is the quantum foam. We can observe that there are subatomic particles, like an electron and anti-electron, constantly popping into existence and annihilating each other. This happens even in an absolute vacuum. The cacophony it causes is called “quantum foam”.
It’s a stretch, but since we observe little particles popping into existence without cause, what prevents a whole universe from popping into existence?
Of course this ignores the “finely tuned universe” argument. There are now hundreds of parameters that have been identified that are finely tuned such that we can exist. If gravity were just a tiny bit stronger, life would be impossible for one reason, but if it were a tiny bit weaker, life would be impossible for another reason. The same is true for lots of other parameters.
So how do they avoid recognizing that the universe and our bodies were designed? Great faith.